Depth cameras can be used to find the topology of a viewed scene. Whereas a conventional digital camera is capable of assigning each pixel a light intensity and/or color value, a depth camera is capable of assigning each pixel a depth value. The depth value is indicative of a distance between the depth camera and a surface observed at the relevant pixel, and the captured depth values are useable to construct a depth image. Even with a very accurate depth image from a depth camera, it can be challenging to identify different objects from the scene using the depth information.